2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28226The probability distribution for the number of top to bottom spanning clusters in Directed percolation in two and three dimensions appears to be universal and is of the form $P(n) \sim \exp(-αn^2)$. We argue that $α$ is a new critical quantity vanishing at the upper critical dimension. The probability distribution of the individual masses of the spanning clusters is found to have a Pearson distribution with a lower cutoff. Various properties of the clusters are reported.5 pages revtex including 4 figures, to appear in Physical Review LettersStatistical MechanicsDisordered Systems and Neural Networkstext